Astigmatic keratotomy (AK)

Astigmatic keratotomy is similar to RK, but its purpose is to correct only astigmatism. Usually, one or two incisions are made in the peripheral cornea to make it more round (as if loosening the laces on a football). This procedure is often combined with RK and has a similar long track record.

AK is a reasonable procedure for correcting pure astigmatism (patients without coexisting nearsightedness or farsightedness) with results that are almost as good as those with LASIK and PRK. AK can also be used to enhance the results of LASIK and PRK by correcting small residual amounts of astigmatism. The most frequent use of AK today is to correct astigmatism at the time of lens implant surgery (either cataract or clear lens extraction surgery).